Physicians overestimate degree of stenosis, prompting inappropriate PCIs

A cross-sectional study of nearly 1,300 patients revealed Chinese physicians systematically overestimate the severity of coronary stenosis, perhaps even more so than in the United States, likely leading to many patients being inappropriately treated with percutaneous coronary intervention (PCI).

For 1,295 patients undergoing PCI, physician visual assessment (PVA) yielded an average 16 percent overestimation of stenosis when compared to computer-assisted quantitative coronary angiography (QCA) in patients without acute MI. For patients diagnosed with acute MI, the average overestimation by physicians was 10.2 percent.

“For coronary lesions treated with PCI in China, PVA reported substantially higher readings of stenosis severity than QCA, with large variation across hospitals and physicians,” wrote lead researcher Haibo Zhang, MD, and colleagues in JAMA Internal Medicine. “These findings highlight the need to improve the accuracy of information used to guide treatment decisions in catheterization laboratories.”

The American College of Cardiology/American Heart Association Appropriate Use Criteria define significant coronary stenosis as 70 percent or greater luminal diameter narrowing by visual assessment. In Zhang et al.’s study, 50.6 percent of patients without acute MI who were deemed to meet this threshold by PVA actually fell below that barrier when assessed by QCA. All angiograms were reviewed with QCA by two independent core laboratories blinded to physicians’ readings.

“Given that the clinical standard, PVA, frequently resulted in an overestimate of lesion severity compared with the less subjective QCA, it is possible that revascularization would not have been pursued in some lesions—an implication that is similar to findings from the United States,” Zhang and coauthors wrote.

The U.S. study showed an average 8 percent overestimation of stenosis for non-MI patients, half of the difference observed in China. Likewise, the incorrect categorization of significant stenosis by PVA was halved in the U.S. cohort—one-fourth versus one-half in the Chinese study.

Zhang et al. pointed out PVA is convenient and efficient and can lead to quick treatment decisions. But inaccurate interpretations may also lead to overtreatment of patients with stable angina—a concern echoed by Rita F. Redberg, MD, MSc, in an editor’s note.

“This enthusiasm for use of PCI, whether motivated by our love for technology, feeling like we are doing something when we open a stenosis, or related to our fee-for-service health care system, is hard to resist once a patient reaches the catheterization laboratory,” wrote Redberg, with the department of medicine at the University of California, San Francisco. “The best approach is not to refer these stable patients to the catheterization laboratory in the first place, but rather to start medical therapy and follow the patient clinically.”